Nanoarchitectured Design of Porous Materials and Nanocomposites from Metal‐Organic Frameworks

The emergence of metal‐organic frameworks (MOFs) as a new class of crystalline porous materials is attracting considerable attention in many fields such as catalysis, energy storage and conversion, sensors, and environmental remediation due to their controllable composition, structure and pore size. MOFs are versatile precursors for the preparation of various forms of nanomaterials as well as new multifunctional nanocomposites/hybrids, which exhibit superior functional properties compared to the individual components assembling the composites. This review provides an overview of recent developments achieved in the fabrication of porous MOF‐derived nanostructures including carbons, metal oxides, metal chalcogenides (metal sulfides and selenides), metal carbides, metal phosphides and their composites. Finally, the challenges and future trends and prospects associated with the development of MOF‐derived nanomaterials are also examined.     

Hybrid Crystals Comprising Metal–Organic Frameworks and Functional Particles: Synthesis and Applications

Hybrid crystals containing encapsulated functional species exhibit promising novel physical and chemical properties. The realization of many properties critically depends on the selection of suitable functional species for incorporation, the rational control of the crystallinity of the host materials, and the manipulation of the distribution of the encapsulated species; only a few hybrid crystals achieve this. Here, a novel synthetic method enables the encapsulation of functional species within crystalline metal–organic frameworks (MOFs). Various kinds of single‐crystalline MOFs with incorporated particles are presented. The encapsulated particles can be distributed in a controllable manner, and the hybrid crystals are applied to the heterogeneous catalysis of the reduction of nitroarenes. These findings suggest a general approach for the construction of MOF materials with potential applications; by combining species and MOFs with suitable functionalities, new properties—not possible by other means—may arise.     

Metal‐Organic Frameworks: Metal‐Organic Frameworks: A Rapidly Growing Class of Versatile Nanoporous Materials (Adv. Mater. 2/2011)

Metal‐organic frameworks (MOFs) represent a new class of hybrid organic‐inorganic supramolecular materials comprised of ordered networks formed from organic electron donor linkers and metal cations. They can exhibit extremely high surface areas, as well as tunable pore size and functionality, and can act as hosts for a variety of guest molecules. Since their discovery, MOFs have enjoyed extensive exploration, with applications ranging from gas storage to drug delivery to sensing. This review covers advances in the MOF field from the past three years, focusing on applications, including gas separation, catalysis, drug delivery, optical and electronic applications, and sensing. We also summarize recent work on methods for MOF synthesis and computational modeling.     

Explosives in the Cage: Metal–Organic Frameworks for High‐Energy Materials Sensing and Desensitization

An overview of the current status of coordination polymers and metal–organic frameworks (MOFs) pertaining to the field of energetic materials is provided. The explosive applications of MOFs are discussed from two aspects: one for detection of explosives, and the other for explosive desensitization. By virtue of their adjustable pore/cage sizes, high surface area, tunable functional sites, and rich host–guest chemistry, MOFs have emerged as promising candidates for both explosive sensing and desensitization. The challenges and perspectives in these two areas are thoroughly discussed, and the processing methods for practical applications are also discussed briefly.     

Complex Nanostructures from Materials based on Metal–Organic Frameworks for Electrochemical Energy Storage and Conversion

Metal–organic frameworks (MOFs) have drawn tremendous attention because of their abundant diversity in structure and composition. Recently, there has been growing research interest in deriving advanced nanomaterials with complex architectures and tailored chemical compositions from MOF‐based precursors for electrochemical energy storage and conversion. Here, a comprehensive overview of the synthesis and energy‐related applications of complex nanostructures derived from MOF‐based precursors is provided. After a brief summary of synthetic methods of MOF‐based templates and their conversion to desirable nanostructures, delicate designs and preparation of complex architectures from MOFs or their composites are described in detail, including porous structures, single‐shelled hollow structures, and multishelled hollow structures, as well as other unusual complex structures. Afterward, their applications are discussed as electrode materials or catalysts for lithium‐ion batteries, hybrid supercapacitors, water‐splitting devices, and fuel cells. Lastly, the research challenges and possible development directions of complex nanostructures derived from MOF‐based‐templates for electrochemical energy storage and conversion applications are outlined.     

Surface‐Mounted Metal–Organic Frameworks: Crystalline and Porous Molecular Assemblies for Fundamental Insights and Advanced Applications

Metal–organic frameworks (MOFs) are crystalline coordination polymers, assembled from inorganic nodes connected by organic linker molecules. An enormous surface area, huge compositional variety, regular structure, and favorable mechanical properties are among their outstanding properties. Monolithic MOF thin films, i.e., surface‐mounted metal–organic frameworks (SURMOFs), with high degree of structural order and adjustable defect density, can be prepared on solid substrates using layer‐by‐layer techniques. Recent studies where SURMOFs served as model systems for quantitative studies of molecular interactions in porous media, including diffusion, are reviewed. Moreover, SURMOFs are ideally suited for the incorporation of photoactive molecules as well as to study electrical transport through crystalline molecular assemblies. Recent work has demonstrated that the realization of crystalline chromophore assemblies via the SURMOF approach allows the study of fundamental aspects of exciton transport, exciton channeling, and photon upconversion at internal interfaces in organic semiconductor materials. Due to their crystalline nature, MOF materials are well suited for quantitative comparisons with theoretical results; especially, since defect densities and types can be characterized and varied in a straightforward fashion. The active role of these nanoporous films in advanced applications, like for remote‐controlled release of molecules, membranes with photoswitchable selectivity, and ion‐conductors with adjustable conductivity, are also emphasized.     

Lipid‐PEG‐Folate Encapsulated Nanoparticles with Aggregation Induced Emission Characteristics: Cellular Uptake Mechanism and Two‐Photon Fluorescence Imaging

Folate functionalized nanoparticles (NPs) that contain fluorogens with aggregation‐induced emission (AIE) characteristics are fabricated to show bright far‐red/near‐infrared fluorescence, a large two‐photon absorption cross section and low cytotoxicity, which are internalized into MCF‐7 cancer cells mainly through caveolae‐mediated endocytosis. One‐photon excited in vivo fluorescence imaging illustrates that these AIE NPs can accumulate in a tumor and two‐photon excited ex vivo tumor tissue imaging reveals that they can be easily detected in the tumor mass at a depth of 400 μm. These studies indicate that AIE NPs are promising alternatives to conventional TPA probes for biological imaging.